Hadith: I memorized from the Prophet (may Allah's peace and blessings be upon him) ten Rak‘ahs (units of prayer)

عَنِ ابْنِ عُمَرَ رَضِيَ اللَّهُ عَنْهُمَا قَالَ:
حَفِظْتُ مِنَ النَّبِيِّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ عَشْرَ رَكَعَاتٍ: رَكْعَتَيْنِ قَبْلَ الظُّهْرِ، وَرَكْعَتَيْنِ بَعْدَهَا، وَرَكْعَتَيْنِ بَعْدَ المَغْرِبِ فِي بَيْتِهِ، وَرَكْعَتَيْنِ بَعْدَ العِشَاءِ فِي بَيْتِهِ، وَرَكْعَتَيْنِ قَبْلَ صَلاَةِ الصُّبْحِ، وَكَانَتْ سَاعَةً لاَ يُدْخَلُ عَلَى النَّبِيِّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ فِيهَا، حَدَّثَتْنِي حَفْصَةُ أَنَّهُ كَانَ إِذَا أَذَّنَ المُؤَذِّنُ وَطَلَعَ الفَجْرُ صَلَّى رَكْعَتَيْنِ، وَفِي لَفْظٍ: أَنَّ النَّبِيَّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ كَانَ يُصَلِّي بَعْدَ الْجُمُعَةِ رَكْعَتَيْنِ.
[صحيح] - [متفق عليه بجميع رواياته] - [صحيح البخاري: 1180]

Ibn ‘Umar (may Allah be pleased with him and his father) reported:
I memorized from the Prophet (may Allah's peace and blessings be upon him) ten Rak‘ahs (units of prayer): two Rak‘ahs before Zhuhr and two Rak‘ahs after it, two Rak‘ahs after Maghrib at his home, two Rak‘ahs after ‘Ishā’ at his home, and two Rak‘ahs before the Fajr prayer, an hour when none was allowed to enter upon the Prophet (may Allah's peace and blessings be upon him). Hafsah told me that after the muezzin would make Adhān (call to prayer) and after the break of dawn, the Prophet (may Allah's peace and blessings be upon him) used to offer two Rak‘ahs. Another wording reads: The Prophet (may Allah's peace and blessings be upon him) used to offer two Rak‘ahs after the Friday prayer.
[Authentic hadith] - [Narrated by Bukhari & Muslim due to its all chains of narrators] - [Sahih Bukhari - 1180]

Explanation

‘Abdullah ibn ‘Umar (may Allah be pleased with him and his father) clarifies that some of the voluntary prayers he memorized from the Prophet (may Allah's peace and blessings be upon him) were ten Rak‘ahs, which are called "As-Sunan ar-Rawātib" (regular Sunnah prayers). They are: two Rak‘ahs before Zhuhr and two after it, two Rak‘ahs after Maghrib at his home, two Rak‘ahs after ‘Ishā’ at his home, and two Rak‘ahs before Fajr, and these are ten Rak‘ahs in total. As for the Friday prayer, he used to offer two Rak‘ahs after it.